Bruce H. Ziran, Natalie L. Talboo, and Navid M. Ziran
DEFINITION
A femoral shaft fracture is any fracture of the femoral diaphysis from 5 cm below the lesser trochanter to within 6 to 8 cm of the distal femoral articular surface.
Some fracture lines extend proximal or distal to the shaft and are therefore not considered shaft fractures.
This description is mostly semantic, as the more important aspect of definition is understanding the “personality” of the fracture.
Fractures whose essential element is diaphyseal with “extensions” into the outer regions are different than fractures whose essential element is subtrochanteric or supracondylar with extension into the diaphysis.
In some circumstances there may be enough involvement of proximal or distal aspects that treatment must change.
For the purposes of this chapter, we will focus on fractures that are amenable to antegrade nailing.10
The Abbreviated Injury Scale (AIS) score for an isolated femoral shaft fracture is three, thus making the Injury Severity Score for an isolated femoral shaft fracture a nine.
Open fractures are usually graded according to the Gustilo-Anderson classification, but one must keep in mind that this classification system was designed for the tibia, a subcutaneous bone. Thus, if absorbed energy is considered, theoretically, significantly more energy would be required to fracture a femur and disrupt the soft tissue envelope around a femur than around a tibia. Nonetheless, this system is widely employed in the femur for descriptive purposes.
The fracture classification system previously used most commonly was the Winquist classification, but it has been modified and standardized with the AO/OTA classification, which is the recommended system.16,27
ANATOMY
The femur is the longest bone in the body. It is subject to very high stresses in the proximal region because of the need to transition the forces of body weight via a lever arm (femoral neck) into more axial forces distally. As such, the subtrochanteric area is subject to very high stresses.14
The femur has an anterior bow and is not a circular bone.
Anteriorly and laterally there are flattened surfaces, and posteriorly there is a taper that is confluent with the linea aspera.
The linea aspera is a very thick fascial structure and frequently remains in continuity but separates from the femur.
Entrapment of the linea aspera between the fracture ends may impede closed fracture reduction, especially with simple fracture patterns. The bone ends may need to be “unwound” to effect a reduction.
Both anterior and lateral bowing is important to recognize, especially if abnormal (eg, metabolic bone disease).
The anterior bow has an average radius of curvature of about 120 cm.
If there is excessive bowing, good preoperative planning is needed.
Surgical options for such abnormal bowing include plate fixation or a controlled osteotomy to allow nail placement.16
The endosteal diameter is important to recognize, especially with young or sclerotic bone.
Normal aging and osteoporosis results in a biomechanical adaptation of enlarged inner diameter. Thus, elderly individuals may have a larger-diameter femoral shaft with a thinner cortex. As in other cylindrical tubes, the bending rigidity of the femur is roughly proportional to the radius to the fourth power.
The vascular supply to the femur is from a nutrient artery off the second perforating branch of the profunda femoris, entering posteriorly along the linea aspera.
Normally, periosteal branches supply the outer one quarter to one third of the cortex as the direction of blood flow is centripetally outward from the medulla to the cortex.
Once fracture occurs, a reversal of blood flow occurs from the periosteal vessel, radially inward.
The linea aspera protects many perforating periosteal vessels, except in severe fractures, and may help explain the high healing rate of femoral shaft fractures (about 95%).
There are three thigh compartments: anterior, posterior, and medial.
Thigh compartment syndrome may occur and generally involves the anterior compartment. Frequently, release of the anterior compartment will relieve pressure.
The proximity of the gluteal compartment places it at risk as well. It should also be considered with compartment syndromes.
PATHOGENESIS
Femoral shaft fractures are high-energy injuries in the young; in the elderly simple falls from ground level are sufficient to fracture the femur.
Fracture patterns give clues to the mechanism.
For example, a simple transverse fracture with a butterfly fragment is due to a bending force (eg, T-bone vehicle crash).
Spiral fracture patterns are usually due to torsional forces.
Indirect high-energy mechanisms, such as a fall from a height or motor vehicle crashes, will usually incur a significant initial deformity during the fracture process.
The active and passive recoil of the muscle soft tissue envelope will decrease the initial displacement. Thus, the extent of soft tissue injury can be difficult to appreciate.
Open fractures in this setting are usually “inside-out” injuries.
Direct mechanism fractures are from ballistic injuries, crush injuries, or other weapons (eg, chainsaw, axe).
With these injuries, there may be less initial displacement of the fracture and soft tissues, but the amount of soft tissue injury can still be extensive.
In ballistic injuries, the shock and cavitation can result in extensive tissue necrosis.
In both mechanisms, it is important to recognize that the zone of tissue injury may extend well beyond the fracture site.
NATURAL HISTORY
In the early 20th century, the natural history of femur fractures was poor.
The mortality of wartime femur fracture before and during World War I was approximately 80%. Serendipitous use of a wheeled splint for transport off the battlefield resulted in a precipitous drop in the mortality rate (the Thomas splint was thus developed).
Because surgical techniques were primitive in those times, fears about infection and surgical complications resulted in most fractures being treated in traction.
The outcome was frequently a shortened, rotated, varus malunion of the femur.
Additional problems such as decubiti, venous thromboembolism, and pulmonary infections with prolonged bed rest resulted in high morbidity and mortality by today's standards.
Kuntschner is considered the father of intramedullary nailing.
Kuntschner's original technique was an open nailing, exposing the fracture site, and in the Western nations, poor surgical technique resulted in high rates of infection and nonunion.
As a result, this method of fracture care was abandoned until late into the 1970s.16
Kuntschner's method was resurrected in the United States by early traumatologists, like S. Hansen and M. Chapman, who used Kuntschner's newer technique of “closed” femoral nailing.
The success rate of femoral nailing using closed technique resulted in low morbidity and began a change in practice to what we perform today.
Early studies outlined the benefits of early reamed femoral nailing.
As survival of more traumatized patients increased, a subset of patients who may benefit from “subacute” nailing developed.
Later studies identified patients at risk (eg, pulmonary injury, incomplete resuscitation, and brain injury) who benefited from stabilization of life-threatening injuries before fixation.
This reflects the paradigm shift from early total care (ETC) to damage control orthopedics (DCO).3,19,22
While some have advocated plating in such cases, there have been no studies demonstrating the superiority of one method over the other in terms of patient survival.4
PATIENT HISTORY AND PHYSICAL FINDINGS
Relevant history includes age, sex, mechanism of injury, associated injuries, loss of consciousness, weakness, paralysis, or loss of sensation.
Metabolic conditions and any musculoskeletal conditions should be elucidated if possible.
Patients should be evaluated according to the advanced trauma life support (ATLS) guidelines.
Particular attention should be given to hypotension, since femoral shaft fractures can be associated with up to 3 to 4 L of blood loss. While not solely responsible for hypotension, femur shaft fractures can be a contributory source.
The limb should be aligned and placed in a traction device, such as a Sager splint or a Thomas splint.
These devices should be removed and replaced with skeletal or limb traction because of the risk of skin problems in the perineal or ischial and ankle areas.
It is essential to inspect the affected limb for any open wounds, swelling, and ecchymosis (see Exam Table for Pelvis and Lower Extremity Trauma, page 1).
The extent of the open wound does not always correlate with the degree of soft tissue or fascial stripping due to the fracture.
Vascular evaluation should include manual palpation of the popliteal, posterior tibial, and dorsalis pedis pulses.
It is important to understand that a pulse is a pressure wave and can still be present in the absence of flow.
Alternatively, the absence of pulse does not always mean absence of flow.
Use of Doppler and examination of the contralateral limb are needed.
Hypotension with peripheral vasoconstriction may accompany such injuries.
The limb should be aligned before vascular examination.
Asymmetric or absent pulses warrant a measurement of the ankle-brachial index (ABI).
An ABI less than 0.9 is abnormal.
Arteriography should be considered to rule out vascular injury.
Neurologic evaluation includes motor and sensory function of the femoral and sciatic nerve.
The femoral nerve may be difficult to examine secondary to pain associated with the fracture.
Sciatic nerve function can be evaluated for both peroneal and tibial branches.
The peroneal branch is tested with ankle and toe dorsiflexion and sensation on the top of the foot.
Tibial branch function is tested with ankle and toe plantarflexion as well as sensation to the sole of the foot.
IMAGING AND OTHER DIAGNOSTIC STUDIES
The tenet of imaging a joint above and a joint below should be followed.
Good anteroposterior (AP) and lateral views of the hip, femur, and knee are required.
Such films can be obtained in the operating room but are essential in planning, since the presence of a femoral neck fracture or a fracture about the knee will greatly change the operative tactic.
Attempts should be made to get an internal-rotation AP view of the femoral neck. However, with current trauma algorithms, the commonality of the pelvic CT scan allows imaging of the femoral neck. The scan should be viewed before deciding on the surgical tactic.
If radiographs are normal but the clinical examination suggests injury (eg, unable to bear weight, pain out of proportion to injury), coronal MRI imaging may elucidate an occult fracture.
CT scanning in these situations may not be sensitive enough to find such fractures.
Occult femoral fractures may be hard to identify with preoperative radiographs.
Use of CT scans of the abdomen that go to the level of the femoral neck have been found to be sensitive enough to identify such occult femoral neck fractures and should be done for most cases.23
DIFFERENTIAL DIAGNOSIS
Other injuries may occur concomitantly with femur fractures, including pelvic fractures, acetabular fractures, femoral neck fractures, and ligamentous injuries to the knee.
If an effusion is present in the knee, the index of suspicion for a knee injury should be elevated.
Distal femur fracture may also occur but may not be radiographically evident, especially in osteoporotic bone.
In the absence of a reasonable mechanism, other causes for fracture such as metabolic bone disease or metastatic (or primary) fracture should be ruled out.
NONOPERATIVE MANAGEMENT
Nonoperative management has typically been reserved for patients who are unfit for surgery, patients who are quadriplegic or paraplegic, patients in whom the benefits do not outweigh the risks, or other precluding factors (eg, active infection).
Truly nondisplaced fractures in a compliant and able patient may also be treated nonoperatively.
Infants and young children may also be treated nonoperatively because of their ability to remodel.
Nonoperative management consists of bed rest and skeletal traction (either through the distal femur or proximal tibia) with 20 to 30 lb of weight.
Attention should be given to mechanical and pharmacologic venous thromboembolism prophylaxis if this treatment is considered.
SURGICAL MANAGEMENT
Isolated femur fractures are not urgent. Appropriate evaluation and medical clearance should be performed. It is in the best interests of the patient and system to stabilize the patient expeditiously, but when appropriate resources are available (eg, knowledgeable staff, anesthesia). It is not necessary to stabilize such fractures during off shifts unless indicated for other reasons (eg, open fracture, polytrauma).
Patients with isolated femur fractures should have some method of traction, pain control, and deep vein thrombosis prophylaxis while awaiting surgical intervention.
Currently, statically locked femoral nailing with limited reaming is the standard of care.
The studies by Brumback et al determined that statically locked nails do not affect healing and avoid the problems of malrotation and shortening. Unreamed nails were proposed to limit effects of canal fill and the theoretical concern of infection. Neither concern was proven, and in fact small unreamed nails had the same problems as in the tibia: higher rates of nonunion. Currently, the “ream to fit” technique is used.5–9,26
In the multiply injured patient (Injury Severity Score of more than 18), with pulmonary compromise or head injury, fracture fixation should be delayed until suitably cleared for surgical intervention, and damage control methods with use of a temporary external fixator should be considered.2,4,17,21
Recently, the reamer-irrigator-aspirator has been used to minimize the pressure-induced embolization from the marrow. As studies are ongoing, this method may reduce the risks in the multiply injured patients.
Open fractures can be safely nailed if a thorough débridement and irrigation is performed.
Absorbable antibiotic beads (calcium sulfate, not calcium phosphate, mixed with vancomycin or tobramycin) can be used at the time of definitive closure to provide local antibiotic delivery.20
In severely contaminated fractures, a staged approach using temporary antibiotic beads (using polymethylmethacrylate mixed with vancomycin or tobramycin) and temporary external fixation, followed by nailing within 2 weeks (with or without use of absorbable beads), can be employed.
Conversion of external fixation to intramedullary nails can safely be performed within 2 to 4 weeks, as long as there is no indication of pin tract problems.
In such cases, the risk of infection is increased but acceptable in lieu of prolonged bed rest.
Because of deforming forces in proximal fractures, the proximal segment tends to flex and externally rotate.
Care should be taken to ensure that the posterior cortex of the proximal fragment is not inadvertently reamed away.
In distal fractures, the distal segment tends to flex at the knee (recurvatum of fracture).
With distal fractures, care should be taken to avoid varus or valgus reduction. This can occur because the opening of the medullary canal distally does not have intimate contact with the nail and does not “self-align.”
Transverse fractures may contain a segment of intact linea aspera that peels off the posterior aspect and may get entrapped in the fracture.
It can result in shortening that may be difficult to overcome without either “unwinding” the fracture or opening the fracture site.
In skeletally mature children, intramedullary nailing offers the same benefits as in adults.
Attention should be paid to adolescents with very valgus neck angles, as some have hypothesized that this can increase the risk of avascular necrosis of the femoral head. However, with modern implants, a trochanteric starting point may alleviate such concerns.
Skeletally immature children may still be considered for some form of intramedullary treatment after considering remaining growth, type of fracture, and benefits over other methods of treatment.1,11
Preoperative Planning
All films should be reviewed, with particular attention paid to the presence of an ipsilateral femoral shaft and neck fracture.
The overall condition of the patient and any associated injuries should be contemplated before embarking on a surgical tactic.
In the presence of pelvic or acetabular fracture, pregnancy, or obesity, one should consider a more elegant tactic, such as retrograde nailing, as opposed to antegrade nailing.
If suitable, antegrade nailing in the supine position can be safely performed with proper positioning and knowledge.
Several options have to be considered during preoperative planning. They include:
Table: fracture table or radiolucent
Position: supine or lateral
Entry point: piriformis or trochanteric
Type of nail: cephalomedullary or standard
Use of traction: skeletal, boot, or manual
Strong consideration should be given to checking fine cut CT scans to search for femoral neck fractures when possible. As part of the operative plan, the femoral neck should also be checked radiographically after fixation and prior to leaving the operating suite.
Positioning
Fracture tabl.
Standard fracture tables (eg, those used commonly for hip fractures) can be used for antegrade femoral nailing but are best used for supine position nailing.
A large and well-padded perineal post should be used.
Traction should be used sparingly and only when needed.
The legs should be scissored to facilitate imaging and allow for appropriate countertraction. Placing the opposite leg in lithotomy position can allow rotation of the pelvis when traction is applied.
The ability to image all aspects of the femur should be verified before preparing and draping (FIG 1A).
Radiolucent table.
Newer tables allow free image intensifier access to the lower extremity.
Some of the tables (Jackson table, OSI, California) also provide traction assemblies. These types of tables are suitable for multiple limb operations (FIG 1B).
Our preferred method uses a radiolucent Jackson table with traction apparatus and lateral positioning (FIG 1C).
Supine position
The supine position may be easier for surgeons to visualize anatomic relationships.
It is more difficult to use supine positioning in obese patients.
It may be the preferred position in patients with spinal cord injuries or severe chest injuries.
It can be used with and without traction.
If the supine (floppy) positioning on a radiolucent table is chosen, it helps to position the patient at the edge of the bed with a small bolster under the pelvis.
Preparing and draping should include the posterior aspect of the gluteal area, since crossing the leg over will facilitate access to the piriformis.
Even with the newer trochanteric entry technique and implants, the ability to manipulate the leg in adduction may be useful during the procedure (FIG 1D).
Lateral position
The lateral position facilitates gaining an entry point, especially with a piriformis starting point in obese patients.
It can be used with and without traction.
When using the lateral position, the pelvis is rolled forward about 15 degrees to allow lateral imaging of the proximal femur.
Care should be taken during positioning for proper padding and spinal precautions if occult spinal injury may be present.
FIG 1 • A. Supine positioning on a fracture table with legs scissored. Slight obliquity using a bump under the sacrum helps with hip visualization. B. Supine position without traction on flat-top table. The ipsilateral hip should be close to the edge, and a bump under the sacrum will help with visualization. Standard lateral views of the hip for entry points can be used, but so can frog-leg laterals. C. Lateral position with traction. Skeletal traction in the proximal tibia or distal femur can be used. The perineal post is pictured here in the perineum, which is best for proximal fractures. In fact, little traction is usually needed and the post is frequently positioned under the apex of the fracture and used to overcome gravitational sagging. If traction will be needed, we have found that placing a blanket on the “down” leg and securing the contralateral thigh with a sling of tape coursing in a proximal and oblique fashion will resist moderate amounts of traction. D. Preparation and draping of the leg using a flat-top table without traction should include posterior sections of the buttocks. The leg can be crossed over to gain easier access to the piriformis starting point.
Traction
If traction is used, it frees an assistant and the length and rotation can be “set.”
If manual traction is used, the length and rotation need to be checked before final interlocking.
Skeletal traction can be via the proximal tibia or distal femur.
The surgeon should be careful if there is any ligamentous instability of the knee, as suggested by a knee effusion or other sign of injury.
In such cases, distal femoral traction can be used, and it can be prepared and draped into the operative field.
Use of distal femoral traction can complicate distal interlocking because of the proximity of the traction apparatus with the interlocking site.
Boot traction is a very common alternative.
Unlike tibial or femoral skeletal traction, where the knee is slightly bent, boot traction uses a straight leg (FIG 1A).
Care should be taken to avoid nerve traction injury (eg, avoid prolonged and excessive traction).
Small perineal posts and long durations of traction have been shown to increase the risk of pudendal nerve injury.
If traction is used, it should be first applied to determine the “reducibility” of the fracture. Then it should be reduced during prepping and applied as needed.
Large and well padded perineal posts should be used whenever possible.6,15
TECHNIQUES
SOFT TISSUE DISSECTION
Whether using a cephalomedullary nail or piriformis fossa nail, the surgical approach is similar.
The surgeon palpates the greater trochanter.
For trochanteric entry, the skin incision is based about 4 to 10 cm above the trochanter in line with the femur.
The tensor fascia is incised and the gluteus maximus is gently separated.
The tendinous insertion of the gluteus medius is frequently more distal, and this tendon can be gently spread to identify a bursal area just below the medius and above the minimus.
For piriformis entry, the incision is made about a handbreadth along the line between the trochanter and the posterior superior iliac spine.
Once the gluteus maximus is gently separated, the access to the piriformis is posterior to the medius.
The piriformis fossa can be easily palpated as a “dimpled ledge” behind the trochanter. This anatomic feature is used during the percutaneous approach for proprioceptive feedback during pin placement.
TROCHANTERIC AND PIRIFORMIS FOSSA ENTRY
After soft tissue dissection, the tip of the greater trochanter is palpated. The piriformis fossa is palpated medially.
The ideal starting point for a piriformis fossa nail is in the fossa along the medial upslope of the greater trochanter, since this is most in line with the shaft.
This point may vary between patients and should be confirmed with intraoperative fluoroscopy.
The surgeon can have an assistant adduct the extremity to aid in exposing this spot (TECH FIG 1A).
Once the starting point is identified by palpation and confirmed with fluoroscopy, the cortex is penetrated with either an awl or a threaded Kirschner wire.
Every effort should be given to establishing an accurate starting point (ie, one that is in line with the femoral shaft).
TECH FIG 1 • A. AP image of the correct position of a guide pin for piriformis entry. B. Lateral image of piriformis starting point. The pin need only start in the piriformis; it will frequently course anterior, and care should be taken not to penetrate the anterior cortex. The rigid reamer need only open the top of the bone for access to medullary canal.
If this is not possible, as long as the entry site is collinear with the shaft, the pin can be directed anteriorly.
In these cases, care should be taken not to perforate the anterior cortex (TECH FIG 1B).
In supine nailing, especially with obese patients, this can be very difficult. Adduction of the limb may not always be possible because of body habitus and setup and especially with proximal fractures.
In these cases, preparing under the buttock and accessing from a more posterior approach may allow access to the fossa.
The lateral positioning allows the easiest access, with very few problems. In fact, nailing can be performed percutaneously (described below) with little problem when using the lateral position.
PERCUTANEOUS METHOD OF NAILING
The percutaneous method of nailing29 uses cutaneous landmarks to identify the ideal entry site, which is usually about one full handbreadth (8 cm) from the posterior corner of the trochanter towards the posterior superior iliac spine (TECH FIG 2A).
The incision is a stab wound.
A guide pin is advanced to the trochanteric bursa (TECH FIG 2B).
The pin is “rolled” off the posterior slope of the trochanter and then advanced distally and anteriorly (TECH FIG 2C,D).
A very distinct resistance is felt, as if on a pedestal or ledge of bone. The tip of the pin provides proprioceptive feedback when this occurs, and it can be felt that there are structures anterior and medially, which constitute the “walls” of the fossa.
TECH FIG 2 • A. The cutaneous site for percutaneous nailing, situated about midway and slightly posterior to midpoint between tip of trochanter and posterior superior iliac spine. B. Photograph showing pin driven into piriformis via percutaneous wound. C. The pin usually finds the trochanteric bursa. It is then “rolled” off the back and advanced anterior and distal until a distinct resistance is felt. It should rest on the “ledge” of bone known as the piriformis fossa. D. The pin has a resistance to anterior and distal advancement but can move medial and posterior. E. The rigid reamer advances over the pin to enter the proximal femur. Use of irrigation will help prevent soft tissue catching. F. Insertion of the nail over the guidewire. With use of a bent guidewire and “ream-to-fit” technique, the likelihood of an incarcerated reamer is very low, and exchange of the guidewire with a chest tube is not needed (unless a ball-tip guidewire is used). G. Intraoperative photo of final wounds. H. Entry site wounds are usually about 1.5 cm.
At this point image verification is performed.
If the pin is not coaxial with the femur, what is most important is that the tip of the pin is centered.
The pin is advanced to engage the cortex, and then a 9to 12-mm rigid reamer is used to open the proximal femoral cortex (TECH FIG 2E).
This reamer need only be advanced enough to open the cortex and provide access to medullary contents. Care should be taken not to ream too deeply and perforate the cortex of the proximal femur anteriorly (see Tech Fig 1).
Once this step is accomplished, the remainder of the procedure can be done with standard methods, and instruments are passed via the keyhole skin incision (TECH FIG 2F–-H).
TROCHANTERIC ENTRY, GUIDEWIRE PLACEMENT, AND FRACTURE REDUCTION
After soft tissue dissection (as described previously), the surgeon palpates the tip of the greater trochanter and its anteroposterior dimensions.
Because of the inherent anatomy of the proximal femur, the ideal starting spot for a trochanteric entry nail is at the tip of the greater trochanter (mediolateral) and the junction of the anterior one third and posterior two thirds of the greater trochanter.
This spot may vary from person to person, but the correct starting point is one that is in line with the femoral shaft.
Once the correct starting spot is identified, the outer cortex is penetrated with either an awl or a pointed guidewire (TECH FIG 3A).
In this method, because the abductor mechanism is being split, soft tissue protection is important.
After the starting point is identified, a guidewire is placed into the proximal femur and passed down the canal.
Forceful and jerking motions can be avoided by firmly twisting the guidewire through the cancellous bone.
A gentle J bend at the distal 1 cm of the wire allows the wire to be “bounced” off cortices and to be “steered” in metaphyseal areas (TECH FIG 3B).
The proprioceptive feedback of a wire passing along the medullary canal is similar to the sensation of pushing a stick on a sidewalk.
TECH FIG 3 • A. The entry point for the trochanter is usually on the anterior one-third junction. B. Bent straight guidewire. This helps to “steer” the wire in metaphyseal bone and will prevent reamer heads from disengaging (relevant only in modular designs). C. The “wand.” It is available on some sets, or can be performed with some extraction rods. It is placed over the guidewire into the proximal segment, down to the level of the lesser trochanter. It can manipulate the proximal fragment to aim it into the distal segment, after which the guidewire is advanced into the distal fragment. This is much more desirable than struggling with manual methods. D. F bar. This can be placed around the thigh to effect the desired translation. In out-of-plane deformities, the bar can find the “ideal“ orientation and effect a reduction. E. The joystick method. Small terminally threaded wires can be drilled into the cortex of each segment and used to manipulate the fragments into reduction. Small external fixator pins can also be used and have been previously described. F. Intraoperative image of guidewire passed across fracture.
If the fracture is not reduced sufficiently to easily pass the wire across, there are several techniques available to facilitate reduction and wire passing.
Some nail systems provide a cannulated rod that is placed over the wire and passed into the proximal femur. This rigid wire holder functions as a wand to manipulate the proximal fragment as the wire approaches the fracture so that it can easily be passed across (TECH FIG 3C).
An F or H bar, a crutch, or both can also be useful to manipulate the proximal and distal fragments (TECH FIG 3D).
Sometimes the fracture cannot be perfectly reduced, but enough provisional alignment can be established to pass the guidewire.
If the fracture is unstable and difficult to reduce after numerous attempts, a small incision can be made along the lateral thigh over the fracture and the fracture can be digitally reduced and provisionally aligned.
In some cases, the incision can be lengthened to allow placement of “lobster claw”-type clamps.
Other methods include the use of unicortical “joystick” half-pins from an external fixator set (usually a 5-mm half-pin). Alternatively, 3-mm threaded guide pins can also be used (TECH FIG 3E).
The guidewire position in the distal segment is confirmed with intraoperative fluoroscopy.
The guidewire should be passed down to the distal femur physeal scar and should be center-center on both the AP and lateral views.
MEASUREMENT AND REAMING
Once the guidewire has been placed, the length of the nail is measured either with a measuring device (usually supplied by the intramedullary nail system) or by using a guidewire of the same length.
Placing the second wire at the entry site and measuring what is not overlapping with the inserted wire provides nail length.
Before measuring, the surgeon confirms the proximal position of the ruler on the greater trochanter.
The surgeon should make sure that there is no soft tissue between the ruler and the top of the greater trochanter, as this can artificially increase the length of the nail chosen.
Average nail lengths range from 38 to 42 cm.
Using the radiographs of the femur, the surgeon can estimate the beginning reamer size.
With “tight” canals, reaming should begin with lower sizes, and sequential reaming can begin starting with the lowest size available (usually 8 or 9 mm).
When starting to ream, the surgeon should pay particular attention to keep the reamer medial in the proximal femur to prevent reaming out the posterior or lateral cortex.
If the reamer does not pass easily, the surgeon should check its position with fluoroscopy since the reamer may be hitting cortical bone (usually anteriorly).
Reaming can be increased by 1.0-mm increments until distinct “chatter” is encountered, after which it should increase in 0.5-mm increments.
Once endosteal “chatter” is encountered, reaming should continue for another 1.0 to 2.0 mm, and a nail diameter of 1.0 to 1.5 mm smaller than the largest diameter reamed should be used.
With modern nail designs, most male patients can be treated with 11- to 13-mm nails and most females with 10- to 12-mm nails.
Care should be taken when there is a tendency for a deforming force to allow for “eccentric” reaming (eg, proximal fractures).
In these cases, without attention, eccentric reaming can remove cortical bone and create defects that result in deformity or a nail outside the bone.
NAIL PLACEMENT
If a ball-tipped wire is used, the surgeon should confirm that it can be pulled through the nail or exchanged for a smooth-tip wire.
After the nail has been inserted, its position is checked distally, at the fracture site, and proximally near its insertion site.
The surgeon ensures that the nail is not too proud above the greater trochanter and fossa.
If the fracture site is distracted, traction should be reduced or adjusted to effect a satisfactory reduction.
Length and rotation need to be reconfirmed before interlocking. Several methods can be used.12,13,24,25
Cortical characteristic.
The femur diameter is not symmetric. Variances in cortical thickness can be used to estimate rotation.
Fracture lines can be used to estimate correct rotation.
Radiographic method.
One method checks the true hip lateral with the distal femoral lateral in the intact contralateral femur. The measured difference is mirrored in the fractured side.
In cases of comminution or bilateral fractures, another method can be used to determine or set the rotation. A true lateral of the distal femur is obtained, and the intensifier is then moved orthogonal to this position, and the proximal femur is visualized to obtain a profile of the lesser trochanter. The images are saved for reference, and mirrored on the fractured side, or contralateral side if bilateral.
Surprisingly, rotational deformities appear to be well tolerated, with an average of 28% of patients having a deformity of more than 15 degrees.
Internal rotation is tolerated better than external rotation.
In all cases, a clinical examination of rotation of both legs with the pelvis supine and the hip flexed to 90 degrees can be used to estimate symmetry.
Unless the patient is in extremis, all nails should be statically locked.
The order of interlocking should be considered.
In axially stable cases, the distal segment should be interlocked, and compression applied by back-slapping the nail.
In unstable cases, traction and alignment should be maintained until interlocking is complete. Usually distal interlocking precedes proximal interlocking.5,28
PROXIMAL INTERLOCKING SCREW PLACEMENT
There are guides with each system that allow placement of proximal screws. In general, at least one screw should be placed.
Unless the fracture is stable, the static screw hole should be used, and the hole closest to the fracture is preferred.
DISTAL INTERLOCKING SCREW PLACEMENT
Distal screw placement is usually done with a freehand technique. This can be one of the most challenging parts of the case for some surgeons and the easiest for others.
In general, setup and image positioning can greatly facilitate this part of the procedure.
Using the concentric circle concept, the image intensifier or the leg is rotated to obtain a perfect circle.
If the image is oval or shaped like an eye, the image intensifier is not perpendicular to the axis of the nail, or in other words, parallel or co-axial with the axis of the screw hole.
The goal is to align the axis of the image intensifier with that of the screw hole. Getting perfect circles is the first critical step.
In TECHNIQUES FIGURE 4A, the image intensifier is not aligned in the coronal plane (varus or valgus to the femoral nail).
In TECHNIQUES FIGURE 4B, the image intensifier is not aligned in the axial–transverse plane (rotationally to the nail).
In TECHNIQUES FIGURE 4C, both screw holes in the nail line up, giving the “perfect circle” wherein the image intensifier is co-linear to the axis of the screw hole in the nail.
Next, a drill or scalpel is used to determine the cutaneous location for an incision, which should go through the fascia and to bone.
A drill is centered over the hole and held securely (TECH FIG 4D).
At this point there are two options: the drill can be gently tapped to engage the near cortex, or it can be drilled.
The axis of the drill bit should be aligned with the center of the image intensifier (which is parallel to that of the hole). Thus, if the drill tip is centered over the hole and aligned with the center of the intensifier, it should be co-axial with the axis of the hole.
TECH FIG 4 • A. The perfect circle method for freehand interlocking. If the image appears as two circles overlapped, the shape of an 8 will appear. The central area is elliptical and indicates that the image intensifier axis is not collinear with the axis of the screw holes. The appropriate corrective direction is parallel to the short axis of the central ellipse (or perpendicular to the long axis). In this case, the correction would be in the coronal plane (proximal-to-distal). B. In this situation, the rotation of the image does not match. It will need to be corrected along the path of the C. C. The image of a perfect circle. D. The drill point should be in the middle of the circle. Then the axis of the drill can be made collinear with that of the image intensifier. E. The drill can pass anterior or posterior to the nail and “feel” pretty good. Care should be taken to make sure the drill point does not drift during this motion. Proprioceptive feedback will frequently indicate when the drill passes through the nail and the contralateral cortex. If the drill “kicks” in one direction (anterior or posterior) it may have missed the nail. If it is not aligned in the coronal plane, it may hit the nail. It is important to verify all implant positions before leaving the operating room. F. A method of measuring using the nail as a “yardstick.” If the diameter of the nail is known, then the diameter of the bone at the level of the interlocking hole can be estimated by seeing how many multiples of the nail will fit in that segment. With some practice the accuracy of this technique is impressive: we estimate our accuracy to exceed 90% using this technique.
Once the drill is into the bone and advanced, fluoroscopic verification should be obtained, after which the drill is advanced to the far cortex.
If the drill bit “kicks” or jerks into a different direction or cannot be advanced, it is likely that it either glanced off the nail (missed the hole anteriorly or posteriorly) or is hitting the nail (proximally or distally) (TECH FIG 4E).
Measuremen.
The drill can be removed and measured with a depth gauge or in many systems read directly from the drill guide.
An alternate method, which we have used with surprising accuracy, is to use the known diameter of the nail as a legend.
Comparing the width of the femoral canal at the level of the screw hole with that of the nail and estimating the number of nail widths in that segment allows for an estimate of the screw length.
With a little practice, this method is fairly reliable, especially considering that many companies provide screws only in 5-mm increments (TECH FIG 4F).
POSTOPERATIVE CARE
Postoperative radiographs should be obtained to check fracture alignment, rotation, and nail and screw placement as well as to ensure the integrity of the femoral neck.
A clinical examination for rotation of the hip and a thorough knee examination are needed to rule out occult knee injury.
Most femoral fractures, irrespective of comminution, can be allowed weight bearing as tolerated.
Care should be taken when fracture lines are within 6 to 8 cm of the interlocking sites. In these cases, higher stresses can result in complications of the nail or delayed healing, and weight bearing can be initiated with radiographic initiation of healing (callus).
Patients should be provided with physiotherapy for range of motion of the knee and hip and encouraged to exercise the abductors as well.
Deep vein thrombosis prophylaxis should be considered for all patients, unless contraindicated.
OUTCOMES
The femur can be expected to heal in about 95% of cases, with an infection rate of about 1% (FIGS 2 AND 3).
Knee motion should return to normal about 12 weeks postoperatively, but may be limited in head-injured or polytrauma patients owing to heterotopic bone formation or lack of early motion.18
While healing rates are good, there is almost always an objective deficit in outcomes, which may or may not be clinically relevant.
Objective examination can reveal deficits in endurance and strength, weather-related symptoms, or residual hip, thigh, and knee pain.
Much like tibial nailing, the causes of such symptoms have not been well elucidated.
COMPLICATIONS
Iatrogenic femoral neck fracture
Up to 15 degrees of rotational malalignment can be well tolerated, but greater than 15 degrees should be corrected.
Rotational deformity can be prevented by paying close attention to cortical thickness, since the femur is not perfectly cylindrical and cortical thickness varies.
Angular malalignment can be defined as greater than 5 degrees of angulation in coronal or sagittal planes.
The overall rate of malalignment is 7% to 11%, with most angular deformities occurring at the proximal and distal thirds of the femur.16
FIG 2 • Radiograph demonstrating initial damage control measures using external fixation. The one proximal pin was advanced to gain bicortical purchase.
FIG 3 • Final radiographs demonstrating final fixation.
Up to 1.5 cm of leg-length discrepancy may be well tolerated.
Beyond 2 cm, many patients will eventually complain of symptoms of malalignment (eg, back, knee, or ankle pain).
While symptoms should resolve with simple shoe modifications, most patients are not able to maintain compliance.
Infection is an infrequent but devastating complication. It can be treated by several methods.
If the infection is early and fixation is stable, local and systemic antibiotic treatment with nail retention may be considered.
If the infection is extensive, a staged procedure should be considered with use of a temporary custom-fabricated antibiotic-impregnated intramedullary device, possibly an external fixator, and a course of intravenous antibiotics.
If the infection is delayed and the fracture is partially healed, one can also consider an exchange nail with reaming and placement of a nail of greater size (usually 2 mm).
Most femur fractures should be considered for a combination of mechanical and pharmacologic prophylaxis against deep vein thrombosis.
Fat emboli are a rare occurrence.
Studies on the reamer-irrigator-aspirator are pending. This device may prevent fat emboli.
Decreased hip function and muscle weakness of the hip abductors and external rotators, along with trochanteric pain, thigh pain, and limp, may occur.
There is a small but definite occurrence of hip dysfunction with femur fractures.
While it still occurs with even retrograde nailing, the incidence seems to be greater with antegrade nails, but recent data using a trochanteric starting point appear promising.
Further and more definitive studies are warranted. There is no superior method.
Heterotopic ossification may occur in 9% to 60% of patients, with the most commonly associated factor being head injury.
Failed hardware or refracture usually indicates a nonunion. In some cases, fracture of locking screws serves to “autodynamize” the fracture and healing ensues.
There is no need for hardware removal or additional surgery if the fracture heals with minimal deformity.
Stretch injury of the sciatic nerve due to prolonged traction during intramedullary nailing can be avoided with judicious use of traction.
Treatment consists of expectant and supportive treatments.
Pudendal nerve palsy (if intramedullary nailing is performed on a fracture table) can occur when excessive traction and a small perineal post are used.
Most femur fractures can be brought to length easily, and traction should be limited to the time of reduction and nail passage and interlocking.
Use of a large, well-padded perineal post, judicious traction, or a femoral distractor can avoid this problem.
Compartment syndrome of the thigh (especially in intubated, polytrauma victims) may occur, especially with crush injuries or prolonged hypotension.
Clinical signs should be used to dictate treatment, and release of the anterior compartment is generally sufficient.
If compartment pressures are to be monitored, threshold pressure is 30 or 40 mm Hg or one that is based on the patient's diastolic blood pressure (within 30 mm Hg).
REFERENCES
1. Anglen JO, Choi L. Treatment options in pediatric femoral shaft fractures. J Orthop Trauma 2005;19:724–733.
2. Bone LB, Anders MJ, Rohrbacher BJ. Treatment of femoral fractures in the multiply injured patient with thoracic injury. Clin Orthop Relat Res 1998;347:57–61.
3. Bone LB, Johnson KD, Weigelt JK, et al. Early versus delayed stabilization of femoral fractures: a prospective randomized study. J Bone Joint Surg Am 1989;71A:336–340.
4. Bosse MJ, MacKenzie EJ, Riemer BL, et al. Adult respiratory distress syndrome, pneumonia, and mortality following thoracic injury and a femoral fracture treated either with intramedullary nailing with reaming or with a plate: a comparative study. J Bone Joint Surg Am 1997; 79A:799–809.
5. Brumback RJ. The rationales of interlocking nailing of the femur, tibia, and humerus. Clin Orthop Relat Res 1996;324:292–320.
6. Brumback RJ, Ellison TS, Molligan H, et al. Pudendal nerve palsy complicating intramedullary nailing of the femur. J Bone Joint Surg Am 1992;74(10):1450–1455.
7. Brumback RJ, Ellison TS, Poka A, et al. Intramedullary nailing of femoral shaft fractures: part III: long-term effects of static interlocking fixation. J Bone Joint Surg Am 1992;74A:106–112.
8. Brumback RJ, Reilly JP, Poka A, et al. Intramedullary nailing of femoral shaft fractures: part I: decision-making errors with interlocking fixation. J Bone Joint Surg Am 1988;70A:1441–1452.
9. Brumback RJ, Uwagie-Ero S, Lakatos RP, et al. Intramedullary nailing of femoral shaft fractures: part II: fracture-healing with static interlocking fixation. J Bone Joint Surg Am 1988; 70A:1453–1462.
10. Court-Brown C. Femoral diaphyseal fractures. In: Browner BD, Levine A, Jupiter J, et al, eds. Skeletal Trauma, ed 3. Philadelphia: Saunders, 2003:1879–1956.
11. Flynn JM, Schwend RM. Management of pediatric femoral shaft fractures. J Am Acad Orthop Surg 2004;12:347–359.
12. Jaarsma RL, Pakvis DF, Verdonschot N, et al. Rotational malalignment after intrameduallary nailing of femoral fractures. J Orthop Trauma 2004;18:403–409.
13. Jaarsma RL, van Kampen A. Rotational malalignment after fractures of the femur. J Bone Joint Surg Br 2004;86B:1100–1104.
14. Johnson KD, Tencer AF, Sherman MC. Biomechanical factors affecting fractures stability and femoral bursting in closed intramedullary nailing of femoral shaft fractures, with illustrative case presentations. J Orthop Trauma 1987;1:1–11.
15. Kao JT, Burton D, Comstock C, et al. Pudendal nerve palsy after femoral intramedullary nailing. J Orthop Trauma 1993;7(1):58–63.
16. Nork S. Fractures of the shaft of the femur. In: Bucholz RW, Heckman JD, Court-Brown C, et al, eds. Rockwood & Green's Fractures in Adults, ed 6. Philadelphia: Lippincott Williams & Wilkins, 2006:1845–1914.
17. Nowotarski PJ, Turen CH, Brumback RJ, et al. Conversion of external fixation to intramedullary nailing for fractures of the shaft of the femur in multiply injured patients. J Bone Joint Surg Am 2000; 82A:781–788.
18. Ostrum RF, Gruen GS, Zelle BA. Fractures of the femoral diaphysis. In: Baumgaertner MR, Tornetta P III, eds. Orthopedic Knowledge Update: Trauma 3, ed 3. AAOS 2005:387–395.
19. Pape HC, Hildebrand F, Pertschy S, et al. Changes in the management of femoral shaft fractures in polytrauma patients: from early total care to damage control orthopedic surgery. J Trauma 2002; 53:452–462.
20. Rutter JE, de Vries LA, van der Werken C. Intramedullary nailing of open femur fractures. Injury 1994;25:419–422.
21. Scalea TM, Boswell SA, Scott JD, et al. External fixation as a bridge to intramedullary nailing for patients with multiple injuries and with femur fractures: damage control orthopedics. J Trauma 2000;48:612–621.
22. Sprague MA, Yang EC. Early versus delayed fixation of isolated closed femur fractures in an urban trauma center. Bull Hosp Jt Dis 2004;62:58–61.
23. Tornetta P III, Kain MS, Creevy WR. Diagnosis of femoral neck fractures in patients with a femoral shaft fracture. Improvement with a standard protocol. J Bone Joint Surg Am 2007;89(1):39–43.
24. Tornetta P III, Ritz G, Kantor A. Femoral torsion after IM nailing of the femur. J Trauma 1995;213–219.
25. Tornetta P III, Tiburzi D. Antegrade nailing of distal femoral shaft fractures caused by gunshots. J Orthop Trauma 1994; 220–227.
26. Tornetta P III, Tiburzi D. The treatment of femoral shaft fractures using intramedullary interlocked nails with and without reaming: a preliminary report. J Orthop Trauma 1997;89–92.
27. Winquist RA, Hansen ST Jr. Comminuted fractures of the femoral shaft treated by intramedullary nailing. Orthop Clin North Am 1980; 633–648.
28. Yang EC. Inserting distal screws into interlocking IM nails. Orthop Rev 1992;21:779–781.
29. Ziran BH, Smith WR, Zlotolow DA, et al. Clinical evaluation of a true percutaneous technique for antegrade femoral nailing. Orthopedics 2005;28:1182–1186.